In the construction industry, shear walls are often employed to prevent the collapse of structures. A shear wall is designed to resist the overturning moment caused by an earthquake or wind loading. These walls must be securely fastened to the concrete foundation so that the overturning moments do not cause separation of the upper portion of a building structure from its lower portion.
Hold downs are commonly employed to connect a shear wall to the foundation. The most common practices today require precise placement of bolts in the concrete foundation and shear wall.
Typically, prior to curing of the concrete, the bolt is positioned to extend upwardly from the foundation. A conventional hold down bracket includes an L-shaped member having a hole formed in a first leg for receiving the bolt extending upwardly from the foundation. Subsequently, bolts are drilled through the wood frame structure of the shear wall at a position above the foundation. The second leg of the L-shaped member is thus bolted to the lower end of the frame structure. The hold downs must be precisely positioned such that the holes of the bracket are accurately aligned with the bolts. Misalignment of the bolts and holes precludes assembly of the hold down device. This requires labor intensive drilling through the wood frame structure of the shear wall above.